You and I seem to have a lot in common. Been employed, done entrepreneurship, don't mind long hours.
I find it interesting how people navigate these tradeoffs. I'm 38, married with two kids (one 3, the other 6mos). It's BUSY. Especially because my wife has a good career, which for better or worse, is a big part of her identity and something she'll never not do (building architecture). Given that we'll always have her salary, I manage a couple rental properties part time, plus have taken a few swings at getting bootstrapped products out the door with mixed success.
I honestly don't know whether you or I have it "easier". I have friends with stay-at-home spouses. I envy their ability to just go to work and focus. I spent today (Sunday) fixing our dryer, going to the grocery store, and doing other chores a stay-at-home wife might handle during the week. I work almost every weekend doing either housework, tax prep, or other stuff. On the other hand, I know we'll never not eat, so the financial stress is a lot less than a one-income household trying something entrepreneurial. Unless you're either really rich or have saved a lot (and willing to risk it), it's hard seeing how someone in that position, especially with kids in a high COL area, can make it work without taking a big salary out of the company (and getting financing to do it). It seems borderline impossible.
I think raising two kids is at least one "full time job", probably more because it's not just 9-5 Monday-Friday. If you're in a two-working spouse family with kids, I think it's very difficult to work more than 45-50 hours/week, and that's assuming you have daycare. There's just SO MUCH to do. Laundry, groceries, dishes, and meal prep are easily 15-20h/week for a family of four. Add to that taking kids to/from childcare/school, putting them to bed, bathing them, keeping them entertained on the weekends, doctors' appointments, and the rest, it gets tough to work more than 50h/week with a working spouse. I think 70 is basically not doable unless you're OK going days at a time not seeing your kids, and even then, only one spouse/partner can really do it.